During various types of ophthalmic surgical procedures, it is very difficult to maintain the normal configuration of the anterior chamber of the eye. Frequently, the anterior chamber of the eye will collapse during surgical entry into the eye. Collapse of the anterior chamber of the eye and failure to keep the anterior chamber in an uncollapsed state substantially increases the difficulty of various surgical maneuvers and may result in irreversible damage to the vital corneal endothelial cells causing permanent corneal edema and consequent blurred vision.
In the past, various pre-operative methods and operative methods have been attempted to alleviate this problem. These prior art methods have met with varying degrees of success.
In one pre-operative method, osmotic agents are systemically administered to the patient in an attempt to shrink the fluid component of the vitreous humor to reduce the overall volume of the vitreous. When the vitreous volume is reduced, there is less tendency for the anterior chamber of the eye to decompress.
In another pre-operative method, external compression forces are applied to the eyeball and eye socket tissues by massaging or the like before surgical entry is made to effectively reduce the fluid volume of the orbital tissues and the eye so as to reduce the intraocular volume and periocular orbital tissue pressure.
Various prior art operative methods require complete anesthesia and akinesia of the ocular muscles inasmuch as contraction of the eye muscles are transmitted to the eyeball once surgical entry has been made. General anesthesia with nondepolarizing muscle relaxant has been used as has local injectable agents.
In an effort to minimize eyelid pressure which could be transmitted to the sclera, various eyelid speculum devices have been used to keep the eyelids open during surgery. Sometimes, the eyelid opening has to be surgically enlarged to reduce eyelid pressure.
In another operative method, the fluid component of the vitreous is aspirated through a separate entry site to decompress the eye volume. This method, however, may lead to retinal complications and vitreous hemorrhage.
In other prior art techniques, infusion terminals or external metal rings have been sutured to the eye in an effort to alleviate the above problems, but suturing requires additional surgical time and effort, necessitates additional sutural entries into the eye and is not always effective.
It is therefore desirable to provide an improved method and apparatus to prevent collapse of the anterior chamber of the eye.